Modern wireless communication systems are built on an architecture that transfers packets of data from a mobile unit to a base transceiver station (BTS). In these architectures the BTS communicates with a packet control function of a base station controller (BSC/PCF/PCF) which further communicates with a packet data serving node (PDSN). If the mobile device desires a data communication session, the PDSN serves as the termination point for the link layer of the data communication session. The PDSN acts as a gateway for the mobile unit to the public networks.
The operations of this sort of network may become extremely complex as the mobile unit travels from a cell managed by one BTS into a cell managed by a different BTS. If an existing data session is in place, the network must maintain the continuity of the data session but service the data session through other resources that may or may not require other BTSs, BSC/PCF/PCFs or PDSNs. In prior systems, the movement of a mobile unit often required the network to establish a new end to end link for the data session in order to accommodate the moving mobile unit. The time required to format the new data link was inconvenient for the user of the mobile unit because no data could be transmitted while the new link was being formed. In addition, the overlap of resources while the old link is still established and the new link is being formed is an inefficient and expensive waste of network resources.